Characteristics, treatment, and outcomes of Myasthenia Gravis in COVID-19 patients: A systematic review.

OBJECTIVE: Recent studies suggest that the clinical course and outcomes of patients with coronavirus disease 2019 (COVID-19) and myasthenia gravis (MG) are highly variable. We performed a systematic review of the relevant literature with a key aim to assess the outcomes of invasive ventilation, mortality, and hospital length of stay (HLoS) for patients presenting with MG and COVID-19. METHODS: We searched the PubMed, Scopus, Web of Science, and MedRxiv databases for original articles that reported patients with MG and COVID-19. We included all clinical studies that reported MG in patients with confirmed COVID-19 cases via RT-PCR tests. We collected data on patient background characteristics, symptoms, time between MG and COVID-19 diagnosis, MG and COVID-19 treatments, HLoS, and mortality at last available follow-up. We reported summary statistics as counts and percentages or mean±SD. When necessary, inverse variance weighting was used to aggregate patient-level data and summary statistics. RESULTS: Nineteen studies with 152 patients (mean age 54.4 ± 12.7 years; 79/152 [52.0%] female) were included. Hypertension (62/141, 44.0%) and diabetes (30/141, 21.3%) were the most common comorbidities. The mean time between the diagnosis of MG and COVID-19 was7.0 ± 6.3 years. Diagnosis of COVID-19 was confirmed in all patients via RT-PCR tests. Fever (40/59, 67.8%) and ptosis (9/55, 16.4%) were the most frequent COVID-19 and MG symptoms, respectively. Azithromycin and ceftriaxone were the most common COVID-19 treatments, while prednisone and intravenous immunoglobulin were the most common MG treatments. Invasive ventilation treatment was required for 25/59 (42.4%) of patients. The mean HLoS was 18.2 ± 9.9 days. The mortality rate was 18/152 (11.8%). CONCLUSION: This report provides an overview of the characteristics, treatment, and outcomes of MG in COVID-19 patients. Although COVID-19 may exaggerate the neurological symptoms and worsens the outcome in MG patients, we did not find enough evidence to support this notion. Further studies with larger numbers of patients with MG and COVID-19 are needed to better assess the clinical outcomes in these patients.

Peripheral Nerve Blocks Outperform General Anesthesia for Pain Control in Arthroscopic Rotator Cuff Repair: A Systematic Review and Meta-analysis.

PURPOSE: The purpose of this review is to compare the effectiveness of different peripheral nerve blocks and general anesthesia (GA) in controlling postoperative pain after arthroscopic rotator cuff repair (ARCR). METHODS: A Preferred Reporting Items for Systematic Reviews and Meta-Analyses-compliant systematic review was conducted for the period of January 1, 2005, to February 16, 2021, by searching the following databases: PubMed, Cochrane, Embase, and Arthroscopyjournal.org. The primary outcomes of interest included 1-hour, 24-hour, and 48-hour pain scores on a numeric rating scale or visual analog scale (VAS). Inclusion criteria were English language studies reporting on adults (≥18 years) undergoing ARCR with peripheral nerve blockade. To synthesize subjective pain score data at each evaluation time point across studies, we performed random-effects network meta-regression analyses accounting for baseline pain score as a covariate. RESULTS: A total of 14 randomized controlled trials with 851 patients were included in the meta-analysis. Data from six different nerve block interventions, single-shot interscalene brachial plexus nerve block (s-ISB; 37.8% [322/851]), single-shot suprascapular nerve block (s-SSNB; 9.9% [84/851]), continuous ISB (c-ISB; 17.5% [149/851]), continuous SSNB (c-SSNB; 6.9% [59/851]), s-ISB combined with SSNB (s-ISB+SSNB; 5.8% [49/851]), s-SSNB combined with axillary nerve block (s-SSNB+ANB; 4.8% [41/851]), as well as GA (17.3% [147/851]) were included. Our meta-analysis demonstrated that c-ISB block had a significant reduction in pain score relative to GA at 1-hour postoperation (mean difference [MD]: -1.8; 95% credible interval [CrI] = -3.4, -.08). There were no significant differences in VAS pain scores relative to GA at 24 and 48 hours postoperatively. However, s-ISB+SSNB had a significant reduction in 48-hour pain score compared to s-ISB (MD = -1.07; 95% CrI = -1.92, -.22). CONCLUSIONS: It remains unclear which peripheral nerve block strategy is optimal for ARCR. However, peripheral nerve blocks are highly effective at attenuating postoperative ARCR pain and should be more widely considered as an alternative over general anesthesia alone. LEVEL OF EVIDENCE: Level II Systematic review and meta-analysis of Level I and II studies.

Outcomes of acute respiratory distress syndrome in COVID-19 patients compared to the general population: a systematic review and meta-analysis.

INTRODUCTION: Acute respiratory distress syndrome (ARDS) due to coronavirus disease 2019 (COVID-19) often leads to mortality. Outcomes of patients with COVID-19-related ARDS compared to ARDS unrelated to COVID-19 is not well characterized. AREAS COVERED: We performed a systematic review of PubMed, Scopus, and MedRxiv 11/1/2019 to 3/1/2021, including studies comparing outcomes in COVID-19-related ARDS (COVID-19 group) and ARDS unrelated to COVID-19 (ARDS group). Outcomes investigated were duration of mechanical ventilation-free days, intensive care unit (ICU) length-of-stay (LOS), hospital LOS, and mortality. Random effects models were fit for each outcome measure. Effect sizes were reported as pooled median differences of medians (MDMs), mean differences (MDs), or odds ratios (ORs). EXPERT OPINION: Ten studies with 2,281 patients met inclusion criteria (COVID-19: 861 [37.7%], ARDS: 1420 [62.3%]). There were no significant differences between the COVID-19 and ARDS groups for median number of mechanical ventilator-free days (MDM: -7.0 [95% CI: -14.8; 0.7], p = 0.075), ICU LOS (MD: 3.1 [95% CI: -5.9; 12.1], p = 0.501), hospital LOS (MD: 2.5 [95% CI: -5.6; 10.7], p = 0.542), or all-cause mortality (OR: 1.25 [95% CI: 0.78; 1.99], p = 0.361). Compared to the general ARDS population, results did not suggest worse outcomes in COVID-19-related ARDS.

Cognitive deficits among patients surviving aneurysmal subarachnoid hemorrhage. A contemporary systematic review.

BACKGROUND: Subarachnoid hemorrhage (SAH) is associated with high rates of morbidity, including neurological and cognitive deficits that may be difficult to identify and quantify. This review provides an update on the cognitive deficits that may result from spontaneous aneurysmal SAH (aSAH) and identifies factors that may help predict and manage these deficits at discharge and thereafter. MATERIALS AND METHODS: We conducted a systematic review of PubMed and Google Scholar to identify studies published between 2010 and 2019 that assessed cognitive deficits at discharge and during follow-up in patients with aSAH. Full-text articles were assessed for information regarding cognitive testing and factors that may be associated with functional outcomes in this population. RESULTS: We reviewed 65 studies published since 2010 that described the cognitive deficits associated with non-traumatic aSAH. Such deficits may impact functional outcomes, quality of life, and return to work and may result in cognitive impairments, such as memory difficulties, speech problems, and psychiatric disorders. CONCLUSIONS: Patients with aSAH, even those that appear normal at the time of hospital discharge, may harbor cognitive deficits that are difficult to detect, yet can interfere with daily functioning. Further research is needed to provide additional information and to identify stronger correlations to be used in the identification, treatment, and amelioration of long-term cognitive deficits in aSAH patients, including those who are discharged with good clinical outcomes scores.

Efficacy and safety of lopinavir/ritonavir in the treatment of COVID-19: A systematic review.

Objectives: To systematically review the clinical literature reporting the use of Lopinavir/ritonavir (LPV/r) for the treatment of patients with Cornonavirus disease 19 (COVID-19) to assess the efficacy of LPV/r for the treatment of COVID-19.Methods: The authors systematically searched PubMed and MedRxiv databases for studies describing treatment of COVID-19 patients using LPV/r compared to other therapies. Articles were excluded if they were case reports, opinion editorials, preclinical studies, single-armed studies, not written in English, not relevant to the topic, or published before May 2020. The included outcomes were viral clearance as measured by reverse-transcription polymerase chain reaction (RT-PCR) negativity and/or improvement on chest computed tomography (CT), mortality, and adverse events.Results: Among 858 total studies, 16 studies met the inclusion criteria and were included in the qualitative review. These studies consisted of 3 randomized control trials, 3 open-label trials, and 10 observational studies. Most of these studies did not report positive clinical outcomes with LPV/r treatment.Conclusion: The systematic review revealed insufficient evidence of effectiveness and clinical benefit of LPV/r in the treatment of COVID-19 patients. Specifically, LPV/r does not appear to improve clinical outcome, mortality, time to RT-PCR negativity, or chest CT clearance in patients with COVID-19.

Superficial temporal artery to middle cerebral artery (STA-MCA) bypass via retrograde arterial anastomosis in a patient with common carotid artery occlusion: a case report.

The standard superficial temporal artery to middle cerebral artery (STA-MCA) bypass depends on adequate antegrade flow in the STA. In the setting of occlusion of the common or external carotid arteries, revascularization requires modification of the standard bypass procedure. A patient with prior history of irradiation for head and neck carcinoma presented with an ischemic injury and fluctuating neurologic deficit not responsive to medical therapy. His left common carotid artery was occluded, but angiographic evaluation demonstrated retrograde filling of his left STA. Reverse STA-MCA bypass was performed, taking advantage of spontaneous collateralization which allowed for retrograde filling of the STA.

The TRAIL: TRAILshort Axis in HIV Immunopathology.

Accelerated loss of HIV-infected and uninfected CD4 T cells is a hallmark of HIV infection that leads to severe immunodeficiency, rendering the host susceptible to opportunistic infections and malignancies. Obstacles to eradicating HIV involve the virus's ability to remain in a quiescent state as latent viral reservoirs and manipulate host defenses to benefit viral survival and persistence of the infected reservoir. Several mechanisms cause CD4 T-cell depletion and recent studies demonstrate the role of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) in this process. Expression of TRAIL and its receptors is upregulated in response to HIV infection. TRAIL interacts with its receptors to activate apoptotic pathways. We recently demonstrated the presence of TRAILshort, a novel splice variant of full-length TRAIL, in the serum of HIV-infected patients. A unique carboxy-terminus allows TRAILshort to bind to death receptors without inducing apoptosis and prevents TRAIL from binding to its receptors, thereby conferring resistance to TRAIL-mediated death. In this review, we describe how the TRAIL: TRAILshort receptor axis modulates apoptosis of different types of immune cells in the context of HIV infection. We also discuss how TRAIL and TRAILshort contribute to the activation of immune cells involved in host defense against HIV and mechanisms that HIV has evolved to manipulate TRAIL for its survival.

Biophysical comparison of soluble amyloid-ß(1-42) protofibrils, oligomers, and protofilaments.

Some of the pathological hallmarks of the Alzheimer's disease brain are senile plaques composed of insoluble amyloid-ß protein (Aß) fibrils. However, much of the recent emphasis in research has been on soluble Aß aggregates in response to a growing body of evidence that shows that these species may be more neurotoxic than fibrils. Within this subset of soluble aggregated Aß are protofibrils and oligomers. Although each species has been widely investigated separately, few studies have directly compared and contrasted their physical properties. In this work, we examined well-recognized preparations of Aß(1-42) oligomers and protofibrils with multiangle (MALS) and dynamic (DLS) light scattering in line with, or following, size-exclusion chromatography (SEC). Multiple SEC-MALS analyses of protofibrils revealed molecular weight (Mw) gradients ranging from 200 to 2600 kDa. Oligomeric Aß species are generally considered to be a smaller and more nascent than protofibrils. However, oligomer Mw values ranged from 225 to 3000 kDa, larger than that for protofibrils. Root-mean-square radius (Rg) values correlated with the Mw trends with protofibril Rg values ranging from 16 to 35 nm, while oligomers produced one population at 40-43 nm with a more disperse population from 22 to 39 nm. Hydrodynamic radius (RH) measurements by DLS and thioflavin T fluorescence measurements indicated that protofibrils and oligomers had commonalities, yet electron microscopy revealed morphological differences between the two. SEC-purified Aß(1-42) monomer at lower concentrations was slower to nucleate but formed protofibrils (1500 kDa) or soluble protofilaments (3000 kDa) depending on the buffer type. The findings from these studies shed new light on the similarities and differences between distinct soluble aggregated Aß species.

The influence of gold surface texture on microglia morphology and activation.

Microglial cells play a critical role in the propagation of neuroinflammation in the central nervous system. Microglia sense and respond to environmental signals including chemical, physical and biological cues from the surrounding cell/tissue components. In this project, our goal was to examine the effects of surface texture on BV-2 microglia morphology and function by comparing flat and nanoporous gold (np-Au) surfaces to the more conventional glass. The biocompatibility of np-Au with microglia was evaluated using functional cell assays and high resolution imaging with scanning electron microscopy (SEM). Microglia seeded on glass, ultra-flat gold (UF-Au), ultra-thin (UT) np-Au and np-Au monolith were adherent to all surfaces and their viability was not compromised as assessed by multiple toxicity assays. SEM revealed detailed morphological characteristics of adherent microglia and indicated few dramatic changes as a result of the different surfaces. Microglia proliferation was hampered by np-Au monolith but less by UT np-Au and not at all on UF-Au or glass. Microglial activation, measured by tumor necrosis factor α (TNFα) production, was fully functional (and equivalent) on all gold surfaces compared to glass. The present findings should help further the understanding of basic microglia biology on textured surfaces and more fully evaluate np-Au as a multi-functional biocompatible material. The knowledge obtained and technology developed will have a significant impact in the fabrication of nanoelectronic devices, chemical sensor development, porous nanostructured materials for BioMEMs/NEMs integration, and functional biomaterial coatings for drug delivery.

Stability of early-stage amyloid-ß(1-42) aggregation species.

Accumulation of aggregated amyloid-ß protein (Aß) is an important feature of Alzheimer's disease. There is significant interest in understanding the initial steps of Aß aggregation due to the recent focus on soluble Aß oligomers. In vitro studies of Aß aggregation have been aided by the use of conformation-specific antibodies which recognize shape rather than sequence. One of these, OC antiserum, recognizes certain elements of fibrillar Aß across a broad range of sizes. We have observed the presence of these fibrillar elements at very early stages of Aß incubation. Using a dot blot assay, OC-reactivity was found in size exclusion chromatography (SEC)-purified Aß(1-42) monomer fractions immediately after isolation (early-stage). The OC-reactivity was not initially observed in the same fractions for Aß(1-40) or the aggregation-restricted Aß(1-42) L34P but was detected within 1-2weeks of incubation. Stability studies demonstrated that early-stage OC-positive Aß(1-42) aggregates were resistant to 4M urea or guanidine hydrochloride but sensitive to 1% sodium dodecyl sulfate (SDS). Interestingly, the sensitivity to SDS diminished over time upon incubation of the SEC-purified Aß(1-42) solution at 4°C. Within 6-8days the OC-positive Aß42 aggregates were resistant to SDS denaturation. The progression to, and development of, SDS resistance for Aß(1-42) occurred prior to thioflavin T fluorescence. In contrast, Aß(1-40) aggregates formed after 6days of incubation were sensitive to both urea and SDS. These findings reveal information on some of the earliest events in Aß aggregation and suggest that it may be possible to target early-stage aggregates before they develop significant stability.

Amyloid-ß(1-42) protofibrils formed in modified artificial cerebrospinal fluid bind and activate microglia.

Soluble aggregated forms of amyloid-ß protein (Aß) have garnered significant attention recently for their role in Alzheimer's disease (AD). Protofibrils are a subset of these soluble species and are considered intermediates in the aggregation pathway to mature Aß fibrils. Biological studies have demonstrated that protofibrils exhibit both toxic and inflammatory activities. It is important in these in vitro studies to prepare protofibrils using solution conditions that are appropriate for cellular studies as well as conducive to biophysical characterization of protofibrils. Here we describe the preparation and characterization of Aß(1-42) protofibrils in modified artificial cerebrospinal fluid (aCSF) and demonstrate their prominent binding and activation of microglial cells. A simple phosphate/bicarbonate buffer system was prepared that maintained the ionic strength and cell compatibility of F-12 medium but did not contain numerous supplements that interfere with spectroscopic analyses of Aß protofibrils. Reconstitution of Aß(1-42) in aCSF and isolation with size exclusion chromatography (SEC) revealed curvilinear ß-sheet protofibrils <100 nm in length and hydrodynamic radii of 21 nm. Protofibril concentration determination by BCA assay, which was not possible in F-12 medium, was more accurately measured in aCSF. Protofibrils formed and isolated in aCSF, but not monomers, markedly stimulated TNFα production in BV-2 and primary microglia and bound in significant amounts to microglial membranes. This report demonstrates the suitability of a modified aCSF system for preparing SEC-isolated Aß(1-42) protofibrils and underscores the unique ability of protofibrils to functionally interact with microglia.

Isolated amyloid-ß(1-42) protofibrils, but not isolated fibrils, are robust stimulators of microglia.

Senile plaques composed of amyloid-ß protein (Aß) are an unshakable feature of the Alzheimer's disease (AD) brain. Although there is significant debate on the role of the plaques in AD progression, there is little disagreement on their role in stimulating a robust inflammatory response within the context of the disease. Significant inflammatory markers such as activated microglia and cytokines are observed almost exclusively surrounding the plaques. However, recent evidence suggests that the plaque exterior may contain a measurable level of soluble Aß aggregates. The observations that microglia activation in vivo is selectively stimulated by distinct Aß deposits led us to examine what specific form of Aß is the most effective proinflammatory mediator in vitro. We report here that soluble prefibrillar species of Aß(1-42) were better than fibrils at inducing microglial tumor necrosis factor α (TNFα) production in either BV-2 and primary murine microglia. Reconstitution of Aß(1-42) in NaOH followed by dilution into F-12 media and isolation with size exclusion chromatography (SEC) revealed classic curvilinear ß-sheet protofibrils 100 nm in length. The protofibrils, but not monomers, markedly activated BV-2 microglia. Comparisons were also made between freshly isolated protofibrils and Aß(1-42) fibrils prepared from SEC-purified monomer. Surprisingly, while isolated fibrils had a much higher level of thioflavin T fluorescence per mole, they were not effective at stimulating either primary or BV-2 murine microglia compared to protofibrils. Furthermore, SEC-isolated Aß(1-40) protofibrils exhibited significantly less activity than concentration-matched Aß(1-42). This report is the first to demonstrate microglial activation by SEC-purified protofibrils, and the overall findings indicate that small, soluble Aß(1-42) protofibrils induce much greater microglial activation than mature insoluble fibrils.

Substituted tryptophans at amyloid-ß(1-40) residues 19 and 20 experience different environments after fibril formation.

Amyloid-ß protein (Aß) is the principal component of the neuritic plaques found in Alzheimer's disease. The predominant Aß morphology in the plaques is fibrillar which has prompted substantial in vitro work to better understand the molecular organization of Aß fibrils. In the current study, tryptophan substitutions were made at Aß(1-40) position 19 (F19W) or 20 (F20W) to ascertain environmental differences between the two residues in the fibril structure. Kinetic studies revealed similar rates of fibril formation between Aß(1-40) F19W and F20W and both peptides formed typical amyloid fibril structures. Aß(1-40) F19W fibrils displayed a significant tryptophan fluorescence blue-shift in λ(max) (33nm) compared to monomer while Aß(1-40) F20W fibrils had a much smaller shift (9nm). Fluorescence quenching experiments with water-soluble acrylamide and KI demonstrated that both W19 and W20 were much less accessible to quenching in fibrils compared to monomer. Lipid-soluble TEMPO quenched the fluorescence of Aß(1-40) F19W fibrils more effectively than F20W fibrils in agreement with the fluorescence blue-shift results. These findings demonstrate distinct environments between Aß(1-40) residues 19 and 20 fibrils and indicate that while W20 accessibility is compromised in Aß fibrils it resides in a much less hydrophobic environment than W19.

Low CD34 collection from a healthy blood progenitor cell donor: a case report.

BACKGROUND: Transplantation of hematopoietic progenitor cells is widely used to ameliorate the consequences of bone marrow failure. In allogeneic transplantation, peripheral blood progenitor cells (PBPCs) from an HLA-matched donor are collected by apheresis and then identified using flow cytometric methods as being CD34 marker positive cells. CASE REPORT: A 25-year-old healthy male was matched with an obese 106 kg 23-year-old female diagnosed with acute lymphoblastic lymphoma. After a routine course of G-CSF induction, a 2-day PBPC collection procedure with a collection volume of 12 L/day was planned. All samples for CD34 estimation were shipped, stored, and tested according to the laboratory standard regulations. Testing was performed per International Society for Hematotherapy and Graft protocol, and CD34+ cells were immunophenotyped using monoclonal antibody against CD34 and CD45 by multicolor flow cytometry. RESULTS: The cumulative yield of both collections was 70.6 x 10(6) CD34+ cells (0.67 x 10(6) CD34+ cells/kg), which fell short of the requested dose of 530 x 10(6) (5 x 10(6) CD34+ cells/kg). Surprisingly, the recipient engrafted successfully and 12 days posttransplant short tandem repeat testing demonstrated only T cells of donor origin in the peripheral blood. CONCLUSION: To our knowledge, no successful engraftment has been reported as yet with such a poor collection of PBPC. The amountof transfused CD34+ cells (0.67 x 10(6)/kg) was significantly less than the minimum required amount (5x 10(6)/kg).

Amyloid-beta(1-42) fibrillar precursors are optimal for inducing tumor necrosis factor-alpha production in the THP-1 human monocytic cell line.

Pathological studies have determined that fibrillar forms of amyloid-beta protein (Abeta) comprise the characteristic neuritic plaques in Alzheimer's disease (AD). These studies have also revealed significant inflammatory markers such as activated microglia and cytokines surrounding the plaques. Although the plaques are a hallmark of AD, they are only part of an array of Abeta aggregate morphologies observed in vivo. Interestingly, not all of these Abeta deposits provoke an inflammatory response. Since structural polymorphism is a prominent feature of Abeta aggregation both in vitro and in vivo, we sought to clarify which Abeta morphology or aggregation species induces the strongest proinflammatory response using human THP-1 monocytes as a model system. An aliquot of freshly reconstituted Abeta(1-42) in sterile water (100 microM, pH 3.6) did not effectively stimulate the cells at a final Abeta concentration of 15 microM. However, quiescent incubation of the peptide at 4 degrees C for 48-96 h greatly enhanced its ability to induce tumor necrosis factor-alpha (TNFalpha) production, the level of which surprisingly declined upon further aggregation. Imaging of the Abeta(1-42) aggregation solutions with atomic force microscopy indicated that the best cellular response coincided with the appearance of fibrillar structures, yet conditions that accelerated or increased the level of Abeta(1-42) fibril formation such as peptide concentration, temperature, or reconstitution in NaOH/PBS at pH 7.4 diminished its ability to stimulate the cells. Finally, depletion of the Abeta(1-42) solution with an antibody that recognizes fibrillar oligomers dramatically weakened the ability to induce TNFalpha production, and size-exclusion separation of the Abeta(1-42) solution provided further characterization of an aggregated species with proinflammatory activity. The findings suggested that an intermediate stage Abeta(1-42) fibrillar precursor is optimal for inducing a proinflammatory response in THP-1 monocytes.

Intravascular hemolysis following low dose daily rifampin.

We report two pediatric patients with rifampin-induced hemolysis following treatment with low daily dose rifampin for methicillin-resistant Staphylococcus aureus (MRSA). With the increased use of rifampin to treat MRSA, physicians should be aware that patients receiving rifampin therapy are at risk for hemolysis, even at low daily doses.

Anaplastic large cell lymphoma: a flow cytometric analysis of 29 cases.

We report our experience with flow cytometric (FC) analysis of 29 cases of anaplastic large cell lymphoma (ALCL). Morphologic analysis of processed cytocentrifuged preparations demonstrated neoplastic cells in 28 cases. In 25 of these, an aberrant lymphoid population was detected by FC analysis. The majority showed high orthogonal light scatter, similar to monocytes or granulocytes. Of the antigens CD2, CD3, CD4, CD5, and CD7, 5 cases expressed 1, 8 expressed 2, 6 expressed 3, 3 expressed 4, and 3 expressed all 5. CD4 was expressed most commonly (20/25 [80%]), followed by CD2 (18/25 [72%]), CD3 (10/25 [40%]), and CD5 and CD7 (8/25 [32%] each). CD45 was expressed in 23 of 25 cases and CD13 in 7 of 9. Of 21 cases, 13 were anaplastic lymphoma kinase (ALK)+, all of which were CD4+, vs 5 of 8 ALK - cases (P = .042). Most ALCLs can be detected and characterized by multiparameter FC analysis. However, light scatter gating on typical lymphoid regions may yield false-negative results in a substantial number of cases.

Presurgical plasma exchange is ineffective in correcting amyloid associated factor X deficiency.

In patients with rare factor deficiencies, for which no factor concentrates are available, plasma exchange (PE) is an option for raising the desired factor level to approximately 80% for surgery. We report a case of acquired factor X (FX) deficiency due to amyloidosis that required urgent surgical repair of an AV fistula aneurysm. This patient had a FX level of 3% at presentation; after 1.5 volume PE with fresh frozen plasma (FFP), his post-exchange FX was only 5%, indicating rapid adsorption of FX to amyloid fibrils. He was managed successfully with FEIBA during surgery.